The invention relates to apparatus by which rope and chain cable may be recovered or payed out.
A typical, though not the only, example of use of the invention is on marine oil drilling rigs and platforms where heavy-duty chain cable used for anchoring the rig or platform is connected to heavy-duty rope and both rope and cable have to be recovered or payed out.
It is known to recover and pay out chain cable using a chain-cable lifter wheel having pockets to receive chain links. Such cable lifter mechanism is used on ships for handling anchor chain. Since very heavy chains are needed for oil drilling rigs or very large ships it is advantageous to use chain cable only for a part of the length of the anchoring element and to use wire or other rope for the remainder. The recovery and paying out of chain cable and rope is required to be performed quickly and safely often under difficult conditions caused by weather and sea conditions. The applicants are not aware that the recovery of a ligament made up of a rope and cable has been achieved using a common lifter wheel, prior to the Applicant's invention.
A particular problem which is overcome by the invention is the provision of a connector which connects the rope to the chain cable but which is compact enough to fit into a pocket on the wheel and which is capable of correct seating on the wheel so as to ensure correct subsequent engagement between the chain cable and the wheel.